Partial hepatectomy-induced polyploidy attenuates hepatocyte replication and activates cell aging events

Area of Science:

• Hepatology
• Regenerative Medicine
• Cell Biology

Background:

• Liver regeneration is crucial for organ function after injury.
• Hepatic polyploidization, an increase in cell DNA content, is a known consequence of liver regeneration.
• The impact of polyploidization on transplanted hepatocyte repopulation remains unclear.

Purpose of the Study:

• To investigate the effects of partial hepatectomy and subsequent hepatic polyploidization on liver repopulation by transplanted hepatocytes.
• To understand how partial hepatectomy influences the proliferative capacity and characteristics of host hepatocytes.

Main Methods:

• Utilized a two-thirds partial hepatectomy model in rodents.
• Employed genetically marked rodent hepatocytes for transplantation studies.
• Analyzed DNA synthesis kinetics, cell ploidy, senescence markers (beta-galactosidase, p21), lipofuscin accumulation, apoptosis, and hepatocyte proliferative capacity in vitro.

Main Results:

• Transplanted hepatocytes did not increase in number after a subsequent partial hepatectomy.
• Partial hepatectomy prior to transplantation led to proliferation of transplanted hepatocytes, with distinct DNA synthesis kinetics compared to host cells.
• Partial hepatectomy induced hepatic polyploidization, depleted diploid hepatocytes, increased senescence markers, and promoted apoptosis in remnant hepatocytes.
• Hepatocytes from partially hepatectomized livers exhibited reduced proliferative capacity in vitro.

Conclusions:

• Partial hepatectomy significantly impairs the repopulation efficiency of transplanted hepatocytes.
• Hepatic polyploidization and associated cellular changes in remnant hepatocytes reduce their proliferative potential.
• These findings offer new insights into liver regeneration mechanisms and the role of cell ploidy in hepatocyte transplantation.